The police investigation into the handling of the casePolice Commissioner Peter Doone announced on 5 May 1997 that Auckland-based region commander Assistant Commissioner Brion Duncan was to conduct a review of the police handling of the Bain murders investigation. He would work under the guidance of the independent Police Complaints Authority.
Mr Doone said the action was being taken because of concern about the impact of criticisms of the police investigation by Auckland businessman Joe Karam in his book David and Goliath.

Mr Doone says he'd been concerned at the publicity given to what he said were unfounded allegations by Joe Karam, but said police could not respond until an independent analysis has been made of the investigation. He also said he was concerned about the effect of the allegations on the New Zealand Police and on the Dunedin investigating officers.

Dunedin officers had approached senior Dunedin administrators asking for the Commissioner to investigate Karam's allegations. However, the Commissioner said he had decided to appoint Mr Duncan to conduct the inquiry before the approach.

Greg O'Connor, president of the NZ Police Association (the police union) said the association was looking into legal options on behalf of the officers named in the book. He said several officers felt their reputations had been damaged.

For details of the outcome of the investigation - see Commissioner’s press statement and the findings of the review panel on this site.